Field of the Invention
This invention relates to electroplating devices and more particularly to a treatment bath for treating items moving therethrough at a constant level, the bath having an end wall configuration to pass the items while maintaining a constant level of liquid in the bath.
Electroplating devices for partially plating items which move in transit at a constant level through at least one treatment bath in which the treatment liquid level is maintained constant and which has end walls with slots therethrough for passing the items in transit at a level below the top of the liquid level are known. Such devices utilize a circulation pump having a delivery side connected to the treatment bath and an intake operatively coupled to an overflow from the end walls of the treatment bath.
This type of continuously operating electroplating device is known, for example, from German Offenlegungsschrift No. 1,796,017. In such prior art electroplating devices, the items to be partially plated, for example, relay springs and the like, are conveyed by a transfer device through a plurality of elongated treatment baths. Only those portions of the items which are actually to be plated are dipped into the liquids in the treatment baths. In order that the items in transit can be moved through the treatment liquids at a uniform level, i.e. at a constant depth of penetration into the liquid, the end walls of the treatment baths have slot openings through which the items can pass. The liquid levels are maintained constant in the treatment bath by means of circulation pumps which recirculate liquid discharging through the slots back into the bath. The actual level of liquid in the bath and, therefore, the depth of submersion of the items passing through the baths, is determined by devices allowing variation in dimensioning of the slots. Such devices have included adjusting plates by means of which the effective depth of the slots can be adjusted.
Because the manipulation of the prior art adjustment plates is a very awkward operation, adjustment and regulation of the liquid level in the treatment baths has involved a considerable amount of time. Further, fluctuations in the quantity of liquids circulating, due for example, to progressing fouling of a filter installed in the pump circuit, give rise to fluctuations of liquid level in the treatment baths which can occur before the adjustment plates can be changed to correct the situation. Thus, an accurate control of the amount of partial plating applied to the items in transit cannot be maintained.
It would therefore be an advance in the art to provide a means for more accurately maintaining the liquid level in the treatment baths.